There are two types of diabetic emergencies: Insulin Shock and Diabetic Coma. The best and easiest way (besides asking the conscious casualty) to determine if the casualty has diabetes is to check to see if they have a medic alert bracelet. This will guide you in determining what first aid you may have to do.
In insulin shock the diabetic casualty needs sugar because they have not ingested enough food to keep their sugar levels up or they have taken too much insulin. Some of the signs of insulin shock are the casualty having a strong and rapid pulse and having shallow breathing. Insulin shock develops very quickly and need medical attention right away. Call 911!!!
In diabetic coma the casualty needs insulin because their body does not produce enough insulin to convert their ingested sugar to energy. Some of the signs of diabetic coma are a weak and rapid pulse and very deep breathing. The effects of diabetic coma take several hours or days to develop and are therefore not as concerning as insulin shock.
Since it can be difficult to determine what kind of diabetic emergency you are encountered with the first aid for both will be the same. Give sugar!! Either some sweet candy, table sugar or orange juice. This will help the casualty in insulin shock immediately but not the casualty in diabetic coma. Since diabetic coma takes hours or days, they have sufficient time to get to a hospital for treatment.
Inform yourself and save a life!!